Electrical controlling system.



A. C. MAGRATH.

ELECTRICAL CONTROLLING SYSTEM.

APPUCATION HLED JUNE 22, I916- Patented Nov. 12, 1918.-

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UNITED STATES PATENT OFFICE.

ARTHUR o. MAGRATH, or BROOKLYN, NEW

YORK, ASSIGNOR T0 WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

Specification of Letters Patent.

Patented Nov. 12, 1918.

Application filed .Tune 22, 1916. Serial No. 105,143.

To all whom it may concern:

Be it known that I, ARTHUR C. MAGRATH, a citizen of the United States, residin at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Electrical Controlling Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to automatic switches, and more particularly to means for controlling the speed of operation of the movable parts of such switches.

The object of this invention is to provide an electromagnetic braking means which serves to retard the motion of the movable parts of an automatic switch.

When a switch in which no cushioning means are provided is operated, especially when driven either by gravity or under spring tension, the resultant shock in overcoming the inertia of the movable parts has a tendency to injure the mechanism of the switch. In the present invention a cushioning effect for such motion is provided by the action of a plunger and a solenoid to which low voltage battery is supplied.

In the embodiment shown the invention is applied to a switch of the structure'disclosed in a patent of C. J. Hendrickson, No. 1,247,399, issued Nov. 20, 1917, but it may obviously be applied to a variety of switch structures.

The invention will be better understood from the following detailed description, reference being had to the accompanying drawings.

In the drawings Figure 1 is a side elevation of the switch shown in the above mentioned application; Fig. 2 is a plan view of parts of the same showing the relation between the releasing armature and the holding pawl.

Since the invention is not limited to any specific structure,only so much of the structure and operation of the switch shown in Figs. 1 and 2 will be described as is necessary to an understanding of the invention.

In the drawings, the invention is shown applied to a line finder switch, motion being rectilinear and continuous; that is, the brush is not advanced step-by-step, but is carried in one continuous movement to the desired contact. The range of the brush may be over any desired number of contacts.

A shaft 8 of non-magnetic material is slidably mounted on suitable bearings (not shown), and is locked from rotation on its axis by a pin 9 set in a fixed support 10, and engaging a slot 11 in the shaft 8. A test brush 12, which may be one of a set, is rigidly and insulatively mounted on said shaft, and is arranged to make contact successively with test contacts 13. In electrical connection with brush 12 through conductor 50, armature and back contact of release magnet 51 andconductor 52, is a tail piece 15, which is arranged to slide over and make contact with a series of commutator strips 16, 16, 16", etc., for a purpose to be explained.

Three solenoids 17, 18 and 19 are placed in alinement as shown, and are mounted in any well-known manner. Cylindrical sections 20 of magnetic material are mounted on the shaft 8, the number of such cores or plungers being determined by the extent of motion required by the brush 12. Each magnetic section is approximately equal in length to the length of the operating solenoids. The: magnetic sections are separated by cylindrical non-magnetic sections 21, the spacing of the magnetic sections being such that after one section has reached the limit of its motion under the control of a particular solenoid, another section will be in operative relation to the solenoid neXt to be actuated. In the drawing, the magnetic sections are indicated by finely dotted portions, this convention being assumed in order that greater clearness may be given to the drawing. A bracket 25 is pivotally mounted by means of pins 96 and 97 and carries three armatures 26 and a pawl 27, the pawl being of non-magnetic material, their relative po sitions being best shown in Fig. 2. The pawl 27 is arranged to engage notches 28 under the tension of a spring 29.

The operation of the switch is as follows: Upon the initiation of a call, battery is connected by the closure of contact 81 in any well-known manner to the contact on which the brush 12 normally rests. A circuit for solenoid 18 is completed from grounded battery 86, contact 81, brush 12, conductor 50, armature and back contact of magnet 51, conductor 52, tail piece 15, a commutator strip 16, conductor 82, winding of solenoid 18, conductors 92, 93, to ground. Solenoid said shaft.

9. In an automatic switch, a movable shaft, a contacting member carried thereby, contacts for engagement by said member, means for producing a shifting magnetic field of a given intensity for setting said shaft, and means for producing a shifting magnetic field of a difierent intensity for applying a braking effort to said shaft during its return movement.

10. In an automatic switch, a movable shaft, a contacting member carried thereby, contacts for engagement by said member, means for producing a magnetic field of a given intensity for setting said shaft, holding means for retaining said shaft in advanced position, and means for producing a magnetic field of a different intensity for applying a braking effort to said shaft in its return movement, said holding means being controlled by said magnetic fields during the setting and return movements of the shaft.

In witness whereof, I hereunto subscribe my name this th day of June A. D., 1916.

ARTHUR C. MAGRATH.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 6. 

